allow for attribute storage of secrets as an alternative

In addition to storing secrets in data bags (the default) we would like
to be able to store them in attributes.

This commit doesn't change the existing passwords API, get_password will
now read from attributes when the node['openstack']['use_databags']
attribute is falsy.

This commit deprecates the development_mode which was only used as a
hack for getting passwords easier without data bags. The attribute
storage of passwords should now be sufficient for all those use cases.

Increased rubocop's methodlength maximum to 15 because there are some
temporary deprecation warnings which add up, but should go away soon.

Change-Id: I1f23878dd3fa83fb40f7b4b56960d57a7b9b89cc
trove needs the tenant_id in the endpoint url

This is documented in the Install Guide: http://docs.openstack.org/trunk/install-guide/install/apt/content/trove-install.html (bottom)

Change-Id: Ief75136c07158d1c61a6db24e5dedddfa4a45fe7
add python_packages attribute for sqlite

this is used by dashboard

Change-Id: I0dff44d05e27ee414c2c70a4515f5997754f2b8f
Blueprint: move-python-db-client-attrs-to-common
Merge "trove needs the tenant_id in the endpoint url"
Add network-related CLI commands

This change introduced the ability to query UUIDs for Neutron entities:
routers, (sub)networks, etc.

To do so, the identity_uuid method was generalised and the image_id
method rewritten to make use of the new get_uuid method.

Change-Id: Idf9f4f04a8ca482ab23c0c667c3546437829690a